LONDON - It’s something that has floated around the fringe of the NBA for a good part of the past decade, going back to the summer of 2004, when the Lakers handed the keys to the franchise to Kobe Bryant by trading Shaquille O’Neal to Miami. The Heat won a championship two years later, but in the intervening time, games between Miami and L.A. had the air of heavyweight title fights. But it was the Shaq-Kobe drama that drew us in — the Lakers were not realistic contenders.

In the summer of 2010, when the Heat put together the trio of LeBron James, Dwyane Wade and Chris Bosh, the Lakers — the defending NBA champs — appeared to be one of the biggest impediments to a Miami championship. But that was before L.A. imploded and got swept in the playoffs by the Dallas Mavericks, the team that actually did win that season’s championship. The Lakers did not recover this past year, slinking out of the playoffs in the second round, while Miami went on to win the title.

Now, though, the elusive Heat-Lakers rivalry — the rivalry that was always just a hair off, timing-wise — gets another crack. The teams have combined to win four of the last seven NBA championships, but have never faced each other in the Finals. For most NBA fans, if there is a reason to love the summer the Lakers have had, with Steve Nash and now Dwight Howard in the fold, it is that L.A. is a powerhouse once again, a counterbalance to the expected dominance of Miami in the East.

The Heat are really good. The Lakers are really good now, too.

There are a lot of moving parts in this four-team trade, and some pretty big gambles being taken. The Denver Nuggets are taking on the contract of Andre Iguodala, hoping that he is a veteran piece who can push them deeper into the playoffs. The Philadelphia 76ers are rolling the dice on Andrew Bynum, waiting to see whether he can stay healthy and, if so, whether he will re-sign long term. The Orlando Magic are simply cutting their losses, letting go another franchise great and crossing their fingers that they have collected enough young assets in return to start a credible rebuilding.

But this deal, more than anything, is about the Lakers. And the Heat. And the fact that, finally, we might get to see Kobe Bryant and LeBron James play each other on the NBA’s biggest stage.

This is no guarantee, of course. The Oklahoma City Thunder, the defending Western Conference champs, are young and only going to get better after reaching the Finals last season — if there is a star approaching the status of Bryant and James, it is Kevin Durant. The San Antonio Spurs, of course, are always worthy of consideration in the West. The Lakers, even with a starting five of Nash, Bryant, Metta World Peace, Pau Gasol and Howard, are aging and susceptible to injury. Bryant is 33, Nash is 38, Gasol and World Peace are both 32. Howard is coming off of back surgery and might not be 100 percent until later in the year. The team is very thin on the bench, and it is fair to wonder whether Mike Brown has the chops to concoct an effective system for these guys.

But this Lakers team has the potential to do in the West whatever Miami does in the East. Bryant has only had a slight drop-off as he has moved into his 30s, and Nash, even at 38, is still one of the top point guards in the league and one of its best shooters. Gasol is better suited to playing a reduced role, working in the high post, and with Howard in the fold, he will be able to do that. Putting Howard, a three-time defensive player of the year, in the middle of the lane will go a long way toward mitigating Nash’s defensive deficiencies, and with his rebounding ability, the Lakers have the personnel to dominate every phase of the game.

With the addition of Ray Allen, and to a lesser extent, Rashard Lewis, the Heat had themselves a pretty good offseason, too. They broke through this year, figured out how to grind through a playoff series and win it in the end. Their talent level, and the fact that their best players are in their primes, seemed to indicate that the Heat were set up for a run of dominance, that they could win the bulk of the titles in the next five years or so. If there was a rival, it was Oklahoma City. The Kobe-LeBron Finals? No chance.

Until now. Again, it is far from a guarantee. But the Lakers and Heat have to be favored to win their conferences. Maybe, at least once, we’ll get to see that Lakers-Heat rivalry play out on the floor in June.